Ultimately the goal is to directly reprogram an adult cell into embryonic stem cells , and from these obtain the cells needed to treat diseases. Nanog is a protein that acts in embryonic stem cells and in the early embryo to keep cells pluripotent.
Silva's team fused embryonic mouse stem cells with nerve-cell stem cells and with ordinary cells from the thymus -- a technology called "cell fusion." During this process, the hybrid cell that is produced is essentially "reprogrammed" with a different set of instructions, including just what type of cell it can develop into once it divides.
Suspecting that Nanog was key to this process, the U.K. team genetically engineered the new cells to produce extra Nanog. The result: "Up to 200 times more hybrid cells were formed," Silva said.